JP5117787B2 - Optical image measuring device - Google Patents

Abstract

Such an optical image measurement device is provided that is capable of acquiring a clear image even when the intensity of an interference light is low. A fundus oculi observation device 1 is configured to superimpose a signal light LS propagated through a fundus oculi Ef and a reference light LR propagated through a reference mirror 174 to generate an interference light LC, detect the interference light LC, and form an image of the fundus oculi Ef. The device 1 determines whether the intensity of a detection signal of the interference light LC is equal to or more than a predetermined threshold and, when determines that the intensity is less than the predetermined threshold, controls to increase the intensity of the detection signal of the interference light LC. The device 1 forms an image of the fundus oculi Ef based on the detection signal with the increased intensity.

Description

  The present invention relates to an optical image measurement device that irradiates a measured object with a light beam and detects interference light based on the reflected light to form an image of the measured object.

  2. Description of the Related Art In recent years, optical image measurement technology that forms an image representing the surface form or internal form of an object to be measured using a light beam from a laser light source or the like has attracted attention. Since this optical image measurement technique does not have invasiveness to the human body like an X-ray CT apparatus, it is expected to be applied particularly in the medical field.

  In Patent Document 1, a measurement arm scans an object with a rotary turning mirror (galvano mirror), and a reference mirror is installed on the reference arm. Further, at the exit, due to interference of light beams from the measurement arm and the reference arm. An optical image measurement device having a configuration in which an interferometer is used in which the intensity of the appearing light is also analyzed by a spectroscope, and the reference arm is provided with a device that changes the phase of the reference light beam stepwise by a discontinuous value. Is disclosed.

  The optical image measuring device of Patent Document 1 uses a so-called “Fourier Domain OCT (Fourier Domain Optical Coherence Tomography)” technique. That is, the object to be measured is irradiated with a beam of low-coherence light, the spectral intensity distribution of the reflected light is acquired, and Fourier transform is performed on the object to measure the form of the object to be measured in the depth direction (z direction). It is to become.

  Furthermore, the optical image measuring device described in Patent Document 1 includes a galvanometer mirror that scans a light beam (signal light), thereby forming an image of a desired measurement target region of the object to be measured. In this optical image measuring device, since the light beam is scanned only in one direction (x direction) orthogonal to the z direction, the image to be formed is in the scanning direction of the light beam (x direction). Is a two-dimensional tomographic image in the depth direction (z direction).

  In Patent Document 2, a plurality of horizontal two-dimensional tomographic images are formed by scanning signal light in the horizontal direction and the vertical direction, and three-dimensional tomographic information of a measurement range is acquired based on the plurality of tomographic images. A technique for imaging is disclosed. Examples of the three-dimensional imaging include a method of displaying a plurality of tomographic images side by side in a vertical direction (referred to as stack data), and a method of rendering a plurality of tomographic images to form a three-dimensional image. Conceivable.

  Patent Document 3 discloses a configuration in which such an optical image measurement device is applied to the ophthalmic field.

  Patent Documents 4 and 5 disclose other types of optical image measurement devices. Patent Document 4 describes an optical image measurement device of a type that scans the wavelength of light irradiated on an object to be measured. This optical image measurement device is called a swept source type.

  Patent Document 5 describes an optical image measurement device that irradiates an object to be measured with light having a predetermined beam diameter and forms an image of a cross section perpendicular to the traveling direction of the light. This optical image measuring device is called a full-field type or an en-face type.

JP 11-325849 A JP 2002-139421 A JP 2003-543 A JP 2007-24677 A JP 2006-153838 A

  In the measurement by the optical image measurement device, the intensity of the interference light may be reduced depending on the state of the object to be measured and a clear image may not be obtained.

  For example, when the translucent body of the eye to be examined is cloudy due to a cataract or the like, the intensity of the signal light passing through the eye to be examined is reduced. As a result, the intensity of the interference light decreases, and a clear image of the fundus may not be obtained.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide an optical image measurement device capable of acquiring a clear image even when the intensity of interference light is low.

To achieve the above object, a first aspect of the present invention divides the light output from the optical source into a signal beam and a reference beam, passed through the reference object and the signal light propagated through the object to be measured Interference light generation means for generating interference light by superimposing reference light, detection means for detecting the interference light and generating a detection signal, and forming an evaluation image of the object to be measured based on the detection signal An image forming unit; a determination unit configured to determine whether the intensity of the detection signal is equal to or greater than a predetermined threshold after the evaluation image is formed; and when the intensity is determined to be less than the predetermined threshold, Control means for performing control so as to increase the intensity of the detection signal, and the image forming means forms an image of the object to be measured based on the detection signal whose intensity has been increased. It is an optical image measuring device.

  The invention according to claim 2 is the optical image measurement device according to claim 1, wherein the detection means receives interference light and converts it into charges, accumulates the charges, and generates a detection signal. The control means increases the intensity of the interference light detection signal by performing control so as to increase the amount of charge accumulated by the detection means.

  The invention according to claim 3 is the optical image measurement device according to claim 2, wherein the control means controls the detection means to increase the accumulation time by increasing the charge accumulation time. It is characterized by increasing.

  The invention according to claim 4 is the optical image measurement device according to claim 3, wherein the interference light generation means includes scanning means for scanning an irradiation position of the signal light on the object to be measured. The control unit controls the scanning unit to scan the signal light at a scanning speed corresponding to the increased accumulation time.

  The invention according to claim 5 is the optical image measurement device according to claim 3, wherein the interference light generation means includes scanning means for scanning the irradiation position of the signal light on the object to be measured. The control means controls the scanning means to sequentially irradiate the signal light to the number of scanning points corresponding to the increased accumulation time.

The invention according to claim 6 is the optical image measurement device according to claim 2, wherein the control means increases the accumulation amount by controlling the light source to increase light output time. It is characterized by that.

  The invention according to claim 7 is the optical image measurement device according to claim 6, wherein the interference light generation means includes scanning means for scanning an irradiation position of the signal light on the object to be measured. The control means controls the scanning means, obtains a scanning speed corresponding to the increased output time, and scans the signal light at the scanning speed.

  The invention according to claim 8 is the optical image measurement device according to claim 6, wherein the interference light generation means includes scanning means for scanning an irradiation position of the signal light on the object to be measured. The control means controls the scanning means to determine the number of scanning points corresponding to the increased output time, and sequentially irradiates the number of scanning points with signal light.

The invention according to claim 9 is the optical image measurement device according to claim 2, wherein the control means increases the accumulation amount by controlling the light source to increase the output intensity of light. It is characterized by that.

  The invention according to claim 10 is the optical image measurement device according to claim 9, wherein the interference light generation means includes scanning means for scanning an irradiation position of the signal light on the object to be measured. The control unit controls the scanning unit to scan the signal light at a scanning speed corresponding to the increased output intensity.

  The invention according to claim 11 is the optical image measurement device according to claim 9, wherein the interference light generation means includes scanning means for scanning an irradiation position of the signal light on the object to be measured. The control unit controls the scanning unit to sequentially irradiate the signal light to the number of scanning points corresponding to the increased output intensity.

  The invention according to claim 12 is the optical image measurement device according to any one of claims 1 to 11, wherein the image forming means obtains a plurality of frequency components of the detection signal. A calculating means, wherein the determining means identifies a minimum value of the intensities of the plurality of frequency components, determines the intensity of the detection signal by determining whether the minimum value is a predetermined value or more, and The control means increases the intensity of the interference light detection signal so that the frequency component corresponding to the minimum value is equal to or greater than the predetermined value when it is determined that the minimum value is less than the predetermined value. And

  The invention according to claim 13 is the optical image measurement device according to any one of claims 1 to 11, wherein the determination means is a pixel value of a plurality of pixels of the image. Determining the intensity of the detection signal by determining whether the maximum value is greater than or equal to a predetermined value, and when the control means determines that the maximum value is less than the predetermined value The intensity of the interference light detection signal is increased so that the pixel value of the pixel corresponding to the maximum value is equal to or greater than a predetermined value.

  The invention according to claim 14 is the optical image measurement device according to any one of claims 1 to 11, wherein the determination means has a pixel value among a plurality of pixels of the image. A pixel that is greater than or equal to a predetermined value is identified, and the intensity of the detection signal is determined by determining whether the number of the identified pixel is greater than or equal to a predetermined number, and the control means has the number less than the predetermined number When it is determined, the intensity of the interference light detection signal is increased so that the number of pixels having a pixel value equal to or greater than a predetermined value is equal to or greater than a predetermined number.

  The invention according to claim 15 is the optical image measurement device according to any one of claims 1 to 11, wherein the determination unit is configured to generate new interference light after control by the control unit. It is determined whether the intensity of the detection signal is greater than or equal to the predetermined threshold, and the control unit controls the light source, the detection unit, and the image forming unit when it is determined that the new intensity is less than the predetermined threshold. Then, two or more images are formed, and a new image is formed by superimposing the two or more images.

  The invention according to claim 16 is the optical image measurement device according to any one of claims 1 to 11, wherein the determination means is configured to generate a new detection signal after control by the control means. It is determined whether the intensity is greater than or equal to the predetermined threshold, and the control unit controls the image forming unit when the new intensity is determined to be less than the predetermined threshold, thereby improving the image quality of the image. It is characterized in that predetermined image processing is performed.

  The invention according to claim 17 is the optical image measurement device according to any one of claims 1 to 11, wherein the determination unit is configured to generate new interference light after control by the control unit. It is determined whether the intensity of the detection signal is greater than or equal to the predetermined threshold, and the control means controls the image forming means when it is determined that the new intensity is less than the predetermined threshold, and the amplitude of the detection signal Is increased to generate a new detection signal, and an image based on the new detection signal is formed.

The invention according to claim 18, splits the light output from the optical source into a signal beam and a reference beam, superimposes the reference light propagated through a reference object and the signal light propagated through the object to be measured an interference light generating means for generating interference light Te, detection means for generating a detection signal upon detection of the interference light, and image forming means for forming an evaluation image of the object to be measured based on the detection signal, the After the evaluation image is formed, a determination unit that determines whether the intensity of the detection signal is greater than or equal to a predetermined threshold; and when the intensity is determined to be less than the predetermined threshold, the light source, the detection signal, and the image An optical image measurement apparatus comprising: a control unit that controls a forming unit to form two or more images, and superimposes the two or more images to form a new image.

The invention according to claim 19, splits the light output from the optical source into a signal beam and a reference beam, superimposes the reference light propagated through a reference object and the signal light propagated through the object to be measured an interference light generating means for generating interference light Te, detection means for generating a detection signal upon detection of the interference light, and image forming means for forming an evaluation image of the object to be measured based on the detection signal, the After the evaluation image is formed, a determination unit that determines whether the intensity of the detection signal is greater than or equal to a predetermined threshold; and when the intensity is determined to be less than the predetermined threshold, the image forming unit is controlled, An optical image measuring device comprising: control means for performing predetermined image processing for improving image quality on an image.

  The invention according to claim 20 is the optical image measurement device according to claim 16 or claim 19, wherein the predetermined image processing is an averaging process for averaging distribution of pixel values in the image. Alternatively, it is a filtering process that corrects pixel values based on pixel values of surrounding pixels for the pixels of the image.

The invention of claim 21 splits the light output from the light source into signal light and reference light, by superimposing the reference light propagated through a reference object and the signal light propagated through the object to be measured Image forming means for forming an image of the object to be measured based on the detection signal, and an interference light generation means for generating interference light and a detection means for detecting the interference light and generating a detection signal Determining means for determining whether the intensity of the detection signal is greater than or equal to a predetermined threshold; and when the intensity is determined to be less than the predetermined threshold, the image forming means is controlled to increase the amplitude of the detection signal And a control unit that generates a new detection signal and forms an image based on the new detection signal.

  The invention according to claim 22 is the optical image measurement device according to claim 17 or 21, wherein the image forming means removes the noise contained in the detection signal to remove the new image. A detection signal is generated.

  According to the present invention, when the intensity of the detection signal of the interference light is less than the predetermined threshold value, the intensity of the detection signal is increased so as to form an image, so that the intensity of the interference light is low. Even a clear image can be obtained.

  According to the present invention, when the intensity of the detection signal of the interference light is less than the predetermined threshold value, two or more images are formed, and these images are superposed to form a new image. Even when the light intensity is low, the image can be clarified.

  According to this invention, when the intensity of the interference light detection signal is less than the predetermined threshold value, the predetermined image processing can be performed on the image. This image processing includes averaging processing and filtering processing. Therefore, the image can be clarified even when the intensity of the interference light is low.

  According to the present invention, when the intensity of the interference light detection signal is less than the predetermined threshold, the amplitude of the interference light detection signal is increased to generate a new detection signal, and an image based on the new detection signal is generated. Since it acts so as to form, the image can be clarified even when the intensity of the interference light is low.

  An example of an embodiment of an optical image measurement device according to the present invention will be described in detail with reference to the drawings.

  An optical image measurement apparatus according to the present invention is an apparatus that forms a tomographic image or a three-dimensional image of an object to be measured using OCT technology. The measurement method to be applied may be any method such as a Fourier domain type, a swept source type, or a full field type. In the case of executing control related to scanning of signal light, an arbitrary measurement method for scanning signal light, such as a Fourier domain type or a swept source type, is applied.

[Device configuration]
In this embodiment, a fundus observation apparatus that acquires an OCT image (tomographic image, three-dimensional image, etc.) of the fundus will be described. A fundus oculi observation device 1 shown in FIG. 1 functions as a Fourier domain type optical image measurement device. In this embodiment, the object to be measured is the fundus.

[overall structure]
As shown in FIG. 1, the fundus oculi observation device 1 includes a fundus camera unit 1 </ b> A, an OCT unit 150, and an arithmetic control device 200. The fundus camera unit 1A has an optical system that is substantially the same as that of a conventional fundus camera. The fundus camera is a device that captures a two-dimensional image of the fundus surface. The OCT unit 150 stores an optical system for acquiring an OCT image. The arithmetic and control unit 200 includes a computer that executes various arithmetic processes and control processes.

  One end of a connection line 152 is attached to the OCT unit 150. A connector 151 for connecting the connection line 152 to the retinal camera unit 1A is attached to the other end of the connection line 152. An optical fiber is conducted through the connection line 152. Thus, the OCT unit 150 and the fundus camera unit 1A are optically connected via the connection line 152.

[Configuration of fundus camera unit]
The fundus camera unit 1A includes an optical system for forming a two-dimensional image of the fundus surface. Here, the two-dimensional image of the fundus surface represents a color image or a monochrome image obtained by photographing the fundus surface, and further a fluorescent image (fluorescein fluorescent image, indocyanine green fluorescent image, etc.). The fundus camera unit 1 </ b> A includes an illumination optical system 100 that illuminates the fundus oculi Ef and a photographing optical system 120 that guides fundus reflection light of the illumination light to the imaging device 10, as in a conventional fundus camera.

  Although details will be described later, the imaging device 10 of the photographing optical system 120 detects illumination light having a wavelength in the near infrared region. The photographing optical system 120 is separately provided with an imaging device 12 that detects illumination light having a wavelength in the visible region. Further, the imaging optical system 120 operates to guide the signal light from the OCT unit 150 to the fundus oculi Ef and guide the signal light passing through the fundus oculi Ef to the OCT unit 150.

  The illumination optical system 100 includes an observation light source 101, a condenser lens 102, a photographing light source 103, a condenser lens 104, exciter filters 105 and 106, a ring translucent plate 107, a mirror 108, an LCD (Liquid Crystal Display) 109, an illumination diaphragm 110, a relay. A lens 111, a perforated mirror 112, and an objective lens 113 are included.

  The observation light source 101 outputs illumination light having a wavelength in the visible region included in a range of about 400 nm to 700 nm, for example. Moreover, the imaging light source 103 outputs illumination light having a wavelength in the near-infrared region included in a range of about 700 nm to 800 nm, for example. Near-infrared light output from the imaging light source 103 is set to be shorter than the wavelength of light used in the OCT unit 150 (described later).

  The photographing optical system 120 includes an objective lens 113, a perforated mirror 112 (hole 112a), a photographing aperture 121, barrier filters 122 and 123, a variable power lens 124, a relay lens 125, a photographing lens 126, a dichroic mirror 134, Field lens (field lens) 128, half mirror 135, relay lens 131, dichroic mirror 136, photographing lens 133, imaging device 10 (imaging device 10a), reflection mirror 137, photographing lens 138, photographing device 12 (imaging device 12a), A lens 139 and an LCD 140 are included.

  Further, the photographing optical system 120 is provided with a dichroic mirror 134, a half mirror 135, a dichroic mirror 136, a reflection mirror 137, a photographing lens 138, a lens 139, and an LCD 140.

  The dichroic mirror 134 reflects the fundus reflection light (having a wavelength included in the range of about 400 nm to 800 nm) of the illumination light from the illumination optical system 100 and the signal light LS (for example, about 800 nm to 900 nm) from the OCT unit 150. Having a wavelength included in the range (described later).

  Further, the dichroic mirror 136 transmits illumination light having a wavelength in the visible region from the illumination optical system 100 (visible light having a wavelength of about 400 nm to 700 nm output from the observation light source 101) and changes the wavelength in the near infrared region. It is configured to reflect the illumination light it has (near infrared light with a wavelength of about 700 nm to 800 nm output from the imaging light source 103).

  The LCD 140 displays a fixation target (internal fixation target) for fixing the eye E to be examined. The light from the LCD 140 is collected by the lens 139, reflected by the half mirror 135, and then reflected by the dichroic mirror 136 via the field lens 128. Further, this light is incident on the eye E through the photographing lens 126, the relay lens 125, the variable power lens 124, the aperture mirror 112 (the aperture 112a thereof), the objective lens 113, and the like. Thereby, the internal fixation target is projected onto the fundus oculi Ef of the eye E to be examined.

  The image sensor 10a is an image sensor such as a CCD (Charge Coupled Devices) or a CMOS (Complementary Metal Oxide Semiconductor) built in the image pickup apparatus 10 such as a TV camera, and particularly detects light having a wavelength in the near infrared region. . That is, the imaging device 10 is an infrared television camera that detects near infrared light. The imaging device 10 outputs a video signal as a result of detecting near infrared light.

  The touch panel monitor 11 displays a two-dimensional image (fundus image Ef ′) of the surface of the fundus oculi Ef based on this video signal. The video signal is sent to the arithmetic and control unit 200, and a fundus image is displayed on a display (described later).

  Note that, for example, illumination light having a near-infrared wavelength output from the photographing light source 103 is used when photographing with the imaging device 10.

  On the other hand, the image pickup device 12a is an image pickup device such as a CCD or a CMOS built in the image pickup device 12 such as a television camera, and particularly detects light having a wavelength in the visible region. That is, the imaging device 12 is a television camera that detects visible light. The imaging device 12 outputs a video signal as a result of detecting visible light.

  The touch panel monitor 11 displays a two-dimensional image (fundus image Ef ′) of the surface of the fundus oculi Ef based on this video signal. The video signal is sent to the arithmetic and control unit 200, and a fundus image is displayed on a display (described later).

  When the fundus is photographed by the imaging device 12, for example, illumination light having a wavelength in the visible region output from the observation light source 101 is used.

  The fundus camera unit 1A is provided with a scanning unit 141 and a lens 142. The scanning unit 141 scans the irradiation position on the fundus oculi Ef of light (signal light LS; described later) output from the OCT unit 150. The scanning unit 141 is an example of the “scanning unit” of the present invention.

  The lens 142 makes the signal light LS guided from the OCT unit 150 through the connection line 152 enter the scanning unit 141 as a parallel light beam. The lens 142 focuses the fundus reflection light of the signal light LS that has passed through the scanning unit 141.

  FIG. 2 shows an example of the configuration of the scanning unit 141. The scanning unit 141 includes galvanometer mirrors 141A and 141B and reflection mirrors 141C and 141D.

  Galvano mirrors 141A and 141B are reflection mirrors arranged so as to be rotatable about rotation shafts 141a and 141b, respectively. The galvanometer mirrors 141A and 141B are rotated around the rotation shafts 141a and 141b by drive mechanisms (mirror drive mechanisms 241 and 242 shown in FIG. 5) described later. Thereby, the direction of the reflection surface (surface that reflects the signal light LS) of each galvanometer mirror 141A, 141B is changed.

  The rotating shafts 141a and 141b are disposed orthogonal to each other. In FIG. 2, the rotation shaft 141a of the galvano mirror 141A is arranged in a direction parallel to the paper surface. Further, the rotation shaft 141b of the galvanometer mirror 141B is disposed in a direction orthogonal to the paper surface.

  That is, the galvano mirror 141B is configured to be rotatable in a direction indicated by a double-sided arrow in FIG. 2, and the galvano mirror 141A is configured to be rotatable in a direction orthogonal to the double-sided arrow. Accordingly, the galvanometer mirrors 141A and 141B act so as to change the reflection direction of the signal light LS to directions orthogonal to each other. As can be seen from FIGS. 1 and 2, when the galvano mirror 141A is rotated, the signal light LS is scanned in the x direction, and when the galvano mirror 141B is rotated, the signal light LS is scanned in the y direction.

  The signal light LS reflected by the galvanometer mirrors 141A and 141B is reflected by the reflection mirrors 141C and 141D and travels in the same direction as when incident on the galvanometer mirror 141A.

  Note that the end surface 152 b of the optical fiber 152 a inside the connection line 152 is disposed to face the lens 142. The signal light LS emitted from the end face 152b travels toward the lens 142 while expanding the beam diameter, and is converted into a parallel light flux by the lens 142. Conversely, the signal light LS that has passed through the fundus oculi Ef is focused toward the end face 152b by the lens 142 and enters the optical fiber 152a.

[Configuration of OCT unit]
Next, the configuration of the OCT unit 150 will be described with reference to FIG. The OCT unit 150 has an optical system for forming an OCT image of the fundus.

  The OCT unit 150 includes almost the same optical system as a conventional optical image measurement device. That is, the OCT unit 150 divides the low-coherence light into reference light and signal light, and superimposes the signal light passing through the eye to be examined and the reference light passing through the reference object to generate interference light and detect it. . This detection result (detection signal) is input to the arithmetic and control unit 200. The arithmetic and control unit 200 analyzes this detection signal to form a fundus tomographic image or a three-dimensional image.

  The low coherence light source 160 is configured by a broadband light source that outputs low coherence light L0. As the broadband light source, for example, a super luminescent diode (SLD) or a light emitting diode (LED) is used. The low coherence light source 160 is an example of the “light source” of the present invention.

  The low coherence light L0 includes, for example, light having a wavelength in the near infrared region and has a temporal coherence length of about several tens of micrometers. The low coherence light L0 has a wavelength longer than the illumination light (wavelength of about 400 nm to 800 nm) of the fundus camera unit 1A, for example, a wavelength included in a range of about 800 nm to 900 nm.

  The low coherence light L0 output from the low coherence light source 160 is guided to the optical coupler 162 through the optical fiber 161. The optical fiber 161 is configured by, for example, a single mode fiber or a PM fiber (Polarization maintaining fiber). The optical coupler 162 splits the low coherence light L0 into the reference light LR and the signal light LS.

  The optical coupler 162 functions as both a means for splitting light (splitter) and a means for superposing light (coupler). Here, it is conventionally referred to as an “optical coupler”. I will call it.

  The reference light LR generated by the optical coupler 162 is guided by an optical fiber 163 made of a single mode fiber or the like and emitted from the end face of the fiber. Further, the reference light LR is collimated by the collimator lens 171 and then reflected by the reference mirror 174 via the glass block 172 and the density filter 173. The reference mirror 174 is an example of the “reference object” in the present invention.

  The reference light LR reflected by the reference mirror 174 passes through the density filter 173 and the glass block 172 again, is condensed on the fiber end surface of the optical fiber 163 by the collimator lens 171, and is guided to the optical coupler 162 through the optical fiber 163.

  Here, the glass block 172 and the density filter 173 serve as delay means for matching the optical path lengths (optical distances) of the reference light LR and the signal light LS, and for matching the dispersion characteristics of the reference light LR and the signal light LS. Acts as dispersion compensation means.

  The density filter 173 also functions as a neutral density filter that reduces the amount of the reference light LR. The density filter 173 is configured by, for example, a rotary ND (Neutral Density) filter. The density filter 173 is rotationally driven by a drive mechanism (a density filter drive mechanism 244 described later; see FIG. 5) configured to include a drive device such as a motor. Thereby, the amount of the reference light LR that contributes to the generation of the interference light LC is changed.

  Further, the reference mirror 174 is movable in the traveling direction of the reference light LR (the direction of the double-sided arrow shown in FIG. 3). Thereby, the optical path length of the reference light LR according to the axial length of the eye E and the working distance (distance between the objective lens 113 and the eye E) can be secured. Further, by moving the reference mirror 174, an image at an arbitrary depth position of the fundus oculi Ef can be acquired. The reference mirror 174 is moved by a drive mechanism (a reference mirror drive mechanism 243 described later; see FIG. 5) configured to include a drive device such as a motor.

  On the other hand, the signal light LS generated by the optical coupler 162 is guided to the end of the connection line 152 by an optical fiber 164 made of a single mode fiber or the like. An optical fiber 152 a is conducted inside the connection line 152. Here, the optical fiber 164 and the optical fiber 152a may be formed from a single optical fiber, or may be formed integrally by joining the respective end faces. In any case, it is sufficient that the optical fibers 164 and 152a are configured to transmit the signal light LS between the fundus camera unit 1A and the OCT unit 150.

  The signal light LS is guided through the connection line 152 and guided to the fundus camera unit 1A. Further, the signal light LS passes through the lens 142, the scanning unit 141, the dichroic mirror 134, the photographing lens 126, the relay lens 125, the variable magnification lens 124, the photographing aperture 121, the hole 112 a of the aperture mirror 112, and the objective lens 113. The eye E is irradiated. When irradiating the eye E with the signal light LS, the barrier filters 122 and 123 are retracted from the optical path in advance.

  The signal light LS incident on the eye E is imaged and reflected on the fundus oculi Ef. At this time, the signal light LS is not only reflected by the surface of the fundus oculi Ef, but also reaches the deep region of the fundus oculi Ef and is scattered at the refractive index boundary. Therefore, the signal light LS passing through the fundus oculi Ef includes information reflecting the surface form of the fundus oculi Ef and information reflecting the state of backscattering at the refractive index boundary of the deep tissue of the fundus oculi Ef. This light may be simply referred to as “fundus reflected light of the signal light LS”.

  The fundus reflection light of the signal light LS travels in the reverse direction in the fundus camera unit 1A, is condensed on the end surface 152b of the optical fiber 152a, enters the OCT unit 150 through the optical fiber 152, and passes through the optical fiber 164. Return to the optical coupler 162.

  The optical coupler 162 superimposes the signal light LS returned through the eye E and the reference light LR reflected by the reference mirror 174 to generate interference light LC. The interference light LC is guided to the spectrometer 180 through an optical fiber 165 made of a single mode fiber or the like.

  In this embodiment, a Michelson interferometer is used. However, for example, any type of interferometer such as a Mach-Zehnder type can be appropriately used.

  The “interference light generating means” of the present invention includes, for example, an optical coupler 162, an optical member on the optical path of the signal light LS (that is, an optical member disposed between the optical coupler 162 and the eye E), and reference light. And an optical member (that is, an optical member disposed between the optical coupler 162 and the reference mirror 174) on the optical path of the LR. In particular, the interference light generating means includes an interferometer including an optical coupler 162, optical fibers 163 and 164, and a reference mirror 174.

  The spectrometer (spectrometer) 180 includes a collimator lens 181, a diffraction grating 182, an imaging lens 183, and a CCD 184. The diffraction grating 182 may be a transmission type diffraction grating that transmits light, or may be a reflection type diffraction grating that reflects light. Further, instead of the CCD 184, other light detection elements such as CMOS can be used.

  The interference light LC incident on the spectrometer 180 is converted into a parallel light beam by the collimator lens 181, and is split (spectral decomposition) by the diffraction grating 182. The split interference light LC is imaged on the imaging surface of the CCD 184 by the imaging lens 183. The CCD 184 detects each spectral component of the separated interference light LC and converts it into electric charges. The CCD 184 accumulates this electric charge and generates a detection signal. Further, the CCD 184 transmits this detection signal to the arithmetic and control unit 200. The time and timing for accumulating charges and the transmission timing of the detection signal are controlled by the arithmetic and control unit 200, for example. The CCD 184 is an example of the “detecting means” in the present invention.

[Configuration of arithmetic control unit]
Next, the configuration of the arithmetic and control unit 200 will be described. The arithmetic and control unit 200 analyzes the detection signal input from the CCD 184 of the OCT unit 150 and forms an OCT image of the fundus oculi Ef. The analysis method at this time is the same as the conventional Fourier domain OCT method.

  Further, the arithmetic and control unit 200 forms a two-dimensional image showing the surface form of the fundus oculi Ef based on the video signals output from the imaging devices 10 and 12 of the fundus camera unit 1A.

  Further, the arithmetic and control unit 200 controls each part of the fundus camera unit 1A and the OCT unit 150.

  As control of the fundus camera unit 1A, the arithmetic control device 200 controls the output of illumination light by the observation light source 101 and the imaging light source 103, and controls the insertion / retraction operation of the exciter filters 105 and 106 and the barrier filters 122 and 123 on the optical path. Then, operation control of a display device such as the LCD 140, movement control of the illumination aperture 110 (control of the aperture value), control of the aperture value of the photographing aperture 121, movement control of the variable power lens 124 (control of magnification), and the like are performed. Furthermore, the arithmetic and control unit 200 controls the operation of the galvanometer mirrors 141A and 141B.

  Further, as the control of the OCT unit 150, the arithmetic and control unit 200 controls the output of the low coherence light L0 by the low coherence light source 160, the movement control of the reference mirror 174, and the rotation operation of the density filter 173 (the amount of decrease in the light amount of the reference light LR Control), control of the accumulation timing and signal output timing of the CCD 184, and the like.

  The hardware configuration of such an arithmetic control device 200 will be described with reference to FIG.

  The arithmetic and control unit 200 has a hardware configuration similar to that of a conventional computer. Specifically, the arithmetic and control unit 200 includes a microprocessor 201, RAM 202, ROM 203, hard disk drive (HDD) 204, keyboard 205, mouse 206, display 207, image forming board 208, and communication interface (I / F) 209. Consists of. These units are connected by a bus 200a.

  The microprocessor 201 includes a CPU (Central Processing Unit), an MPU (Micro Processing Unit), and the like. The microprocessor 201 reads out the control program 204a from the hard disk drive 204 and expands it on the RAM 202, thereby causing the fundus oculi observation device 1 to execute operations characteristic of this embodiment.

  Further, the microprocessor 201 executes control of each part of the device described above, various arithmetic processes, and the like. Further, the microprocessor 201 receives operation signals from the keyboard 205 and the mouse 206, and controls each part of the apparatus according to the operation content. Further, the microprocessor 201 performs control of display processing by the display 207, control of data and signal transmission / reception processing by the communication interface 209, and the like.

  The keyboard 205, the mouse 206, and the display 207 are used as a user interface of the fundus oculi observation device 1. The keyboard 205 is used as a device for inputting, for example, letters and numbers. The mouse 206 is used as a device for performing various input operations on the display screen of the display 207.

  The display 207 is a display device such as an LCD or a CRT (Cathode Ray Tube) display, for example, and displays various images such as an image of the fundus oculi Ef formed by the fundus oculi observation device 1, or an operation screen or a setting screen. Or display various screens.

  The user interface of the fundus oculi observation device 1 is not limited to such a configuration, and may include, for example, a trackball, a joystick, a touch panel LCD, a control panel for ophthalmic examination, and the like. As the user interface, an arbitrary configuration having a function of displaying and outputting information and a function of inputting information and operating the apparatus can be adopted.

  The image forming board 208 is a dedicated electronic circuit that performs processing for forming an image (image data) of the fundus oculi Ef. The image forming board 208 is provided with a fundus image forming board 208a and an OCT image forming board 208b.

  The fundus image forming board 208a is a dedicated electronic circuit that forms image data of a fundus image based on video signals from the imaging device 10 and the imaging device 12.

  The OCT image forming board 208b is a dedicated electronic circuit that forms image data of a tomographic image of the fundus oculi Ef based on a detection signal from the CCD 184 of the OCT unit 150.

  By providing such an image forming board 208, it is possible to improve the processing speed of processing for forming a fundus image or a tomographic image.

  The communication interface 209 transmits a control signal from the microprocessor 201 to the fundus camera unit 1A and the OCT unit 150. The communication interface 209 receives video signals from the imaging devices 10 and 12 and detection signals from the CCD 184 of the OCT unit 150 and inputs them to the image forming board 208. At this time, the communication interface 209 inputs video signals from the imaging devices 10 and 12 to the fundus image forming board 208a and inputs detection signals from the CCD 184 to the OCT image forming board 208b.

  When the arithmetic and control unit 200 is connected to a communication line such as a LAN (Local Area Network) or the Internet, the communication interface 209 includes a network adapter such as a LAN card and a communication device such as a modem. Data communication can be performed via a line. In this case, the fundus oculi observation device 1 can be operated by installing a server for storing the control program 204a on the communication line and configuring the arithmetic control device 200 as a client terminal of the server.

[Control system configuration]
Next, the configuration of the control system of the fundus oculi observation device 1 will be described with reference to FIGS.

(Control part)
The control system of the fundus oculi observation device 1 is configured around the control unit 210 of the arithmetic and control unit 200. The control unit 210 includes a microprocessor 201, a RAM 202, a ROM 203, a hard disk drive 204 (control program 204a), a communication interface 209, and the like.

  The control unit 210 is provided with a main control unit 211 and a storage unit 212. The main control unit 211 performs the various controls described above.

  The storage unit 212 stores various data. As data stored in the storage unit 212, for example, image data of an OCT image, intensity of a detection signal (intensity of each frequency component), subject information (information on the subject such as patient ID and name), and the like. is there. The main control unit 211 performs a process of writing data to the storage unit 212 and a process of reading data from the storage unit 212.

(Image forming part)
The image forming unit 220 forms image data of the fundus oculi image Ef ′ based on the video signals from the imaging devices 10 and 12.

  The image forming unit 220 forms image data of a tomographic image of the fundus oculi Ef based on the detection signal from the CCD 184. This processing includes, for example, noise removal (noise reduction), filter processing, FFT (Fast Fourier Transform), and the like. In particular, the frequency component calculation unit 221 obtains the intensity of the frequency component of the detection signal by performing FFT. Note that the frequency component of the detection signal corresponds to the spectral component of the interference light LC. The frequency component calculation unit 221 is an example of the “calculation unit” of the present invention.

  For example, the image forming unit 220 determines the pixel value (luminance value) based on the intensity of the detection signal, more specifically, the intensity of the frequency component, thereby forming image data of the OCT image. Thus, the detection signal (intensity) and the image data (pixel value) are in a correspondence relationship. In this specification, the intensity of the detection signal may be identified with the pixel value of the image data.

  The image forming unit 220 includes an image forming board 208, a communication interface 209, and the like. In this specification, “image data” and “image” displayed based on the “image data” may be identified.

(Image processing unit)
The image processing unit 230 performs various types of image processing and analysis processing on the image data of the image formed by the image forming unit 220. For example, the image processing unit 230 executes various correction processes such as image brightness correction and dispersion correction. The image processing unit 230 also performs processing related to the detection signal (frequency component) as described later.

  The image processing unit 230 forms image data of a three-dimensional image of the fundus oculi Ef by executing an interpolation process for interpolating pixels between tomographic images formed by the image forming unit 220.

  Note that the image data of a three-dimensional image means image data in which pixel positions are defined by a three-dimensional coordinate system. As image data of a three-dimensional image, there is image data composed of voxels arranged three-dimensionally. This image data is called volume data or voxel data. When displaying an image based on volume data, the image processing unit 230 performs rendering processing (volume rendering, MIP (Maximum Intensity Projection), etc.) on the volume data, and views the image from a specific gaze direction. Image data of a pseudo three-dimensional image is formed. A pseudo three-dimensional image based on the image data is displayed on a display device such as the display 207.

  It is also possible to form stack data of a plurality of tomographic images as image data of a three-dimensional image. The stack data is image data obtained by three-dimensionally arranging a plurality of tomographic images obtained along a plurality of scanning lines based on the positional relationship of the scanning lines.

  The intensity determination unit 231 of the image processing unit 230 determines whether the intensity of the detection signal is equal to or greater than a predetermined threshold. In other words, the intensity determination unit 231 determines whether the pixel of the image data of the OCT image is equal to or greater than a predetermined threshold value. Here, “more than the predetermined threshold” means that it is equal to or exceeds the predetermined threshold, but in the former, it is not necessary to be exactly equal to the predetermined threshold, and the effect of this embodiment is achieved. A degree of error is allowed. The same applies to the term “less than” and the like. The strength determination unit 231 is an example of the “determination means” in the present invention. Hereinafter, an example of processing executed by the strength determination unit 231 will be described.

  The first processing example is based on the frequency component of the detection signal. The detection signal includes a plurality of frequency components. The intensity of each frequency component is acquired by the frequency component calculation unit 221. The intensity determining unit 231 compares the intensities of a plurality of frequency components and specifies the minimum value.

  Next, the strength determining unit 231 determines whether the minimum value is equal to or greater than a predetermined value. This predetermined value is set in advance. The intensity determining unit 231 determines that the intensity of the detection signal is equal to or greater than a predetermined threshold when the minimum value is equal to or greater than the predetermined value. Conversely, when the minimum value is less than the predetermined value, it is determined that the intensity of the detection signal is less than the predetermined threshold.

  The second processing example is based on the pixel value (luminance value) of the pixel of the OCT image (tomographic image). The intensity determining unit 231 compares the pixel values of a plurality of pixels of the OCT image and identifies the maximum value.

  Next, the strength determining unit 231 determines whether the maximum value is equal to or greater than a predetermined value. This predetermined value is set in advance. The intensity determination unit 231 determines that the intensity of the detection signal is equal to or greater than a predetermined threshold when the maximum value is equal to or greater than the predetermined value. Conversely, when the maximum value is less than the predetermined value, it is determined that the intensity of the detection signal is less than the predetermined threshold.

  The third processing example is also based on the pixel value (luminance value) of the pixel of the OCT image (tomographic image). The intensity determination unit 231 specifies a pixel whose pixel value is equal to or greater than a predetermined value among the plurality of pixels of the OCT image. This process can be executed by comparing the pixel value of each pixel with a predetermined value and determining whether the pixel value is greater than or equal to the predetermined value. This predetermined value is set in advance.

  Next, the intensity determination unit 231 determines whether the number of pixels having a pixel value equal to or greater than a predetermined value is equal to or greater than a predetermined number. This process can be executed by counting the number of pixels having pixel values equal to or greater than a predetermined value and comparing the number with a predetermined number. Further, a similar determination may be performed by creating a histogram of pixel values in the OCT image, specifying the number of pixels having a pixel value equal to or greater than a predetermined value, and comparing the number with a predetermined number. This predetermined number is set in advance. The intensity determination unit 231 determines that the intensity of the detection signal is equal to or greater than a predetermined threshold when the number of pixels having a pixel value equal to or greater than the predetermined value is equal to or greater than the predetermined number. On the contrary, when this number is less than the predetermined number, it is determined that the intensity of the detection signal is less than the predetermined threshold.

  The control setting unit 232 operates when the intensity determining unit 231 determines that the intensity of the detection signal is less than a predetermined threshold. The control setting unit 232 sets various control contents for increasing the intensity of the detection signal. The control content includes the output intensity and emission time of the low coherence light L0, the scanning speed and scanning position of the signal light LS, the charge accumulation time by the CCD 184, and the like.

  The output intensity setting unit 233 sets the intensity (brightness) of the low coherence light L0 output from the low coherence light source 160. When the optical image measurement device is applied to the medical field such as the ophthalmology field, the maximum value of the intensity of the low coherence light is set in advance, and the setting of the intensity exceeding the maximum value is prohibited. This is a consideration for avoiding a situation where the low-coherence light L0 (signal light LS) damages the patient and performing the measurement safely. Hereinafter, an example of setting processing of the output intensity of low coherence light will be described.

  As a first processing example, the output intensity setting unit 233 increases the output intensity (original output intensity) of the low-coherence light L0 based on the detection signal that is the determination target by the intensity determination unit 231 by a predetermined amount. Set a new output intensity. The amount of increase at this time is set in advance.

  As a second processing example, the output intensity setting unit 233 sets a new output intensity of the low coherence light L0 based on the difference between the intensity of the detection signal and a predetermined threshold value.

  For example, when the first processing example of the intensity determination unit 231 is applied, the output intensity setting unit 233 subtracts the minimum value from the predetermined value when the minimum value of the frequency component of the detection signal is less than the predetermined value. A new output intensity is set based on the difference value. This process can be performed, for example, by creating and storing information associating the difference value with the increase amount in advance and determining the increase amount based on this information. Further, the increase amount may be calculated from the relationship between the minimum value and the difference value.

  When the second processing example of the intensity determination unit 231 is applied, the output intensity setting unit 233 subtracts the maximum value from the predetermined value when the maximum value of the pixel value is less than the predetermined value, and the value of the difference A new output intensity is set based on This process can be performed, for example, by creating and storing information associating the difference value with the increase amount in advance and determining the increase amount based on this information. Further, the increase amount may be calculated from the relationship between the maximum value and the difference value.

  When the third processing example of the intensity determination unit 231 is applied, the output intensity setting unit 233 subtracts the number from the predetermined number when the number of pixels having a pixel value equal to or greater than the predetermined value is less than the predetermined number. A new output intensity is set based on the difference value. This process can be performed, for example, by creating and storing information associating the difference value with the increase amount in advance and determining the increase amount based on this information. Further, the increase amount may be calculated from the relationship between the number and the difference value.

  The light emission time setting unit 234 sets the output time (light emission time) of the low coherence light L0 from the low coherence light source 160. For example, the light emission time setting unit 234 sets the light emission time in the same manner as the output intensity setting described above. As in the case of the output intensity, the setting of the light emission time that exceeds the maximum amount of light that can be irradiated to the human body is prohibited. This maximum light quantity is set according to, for example, the output intensity.

  The scanning speed setting unit 235 sets the scanning speed of the signal light LS. Here, the scanning speed can be defined as the speed of the signal light LS that scans the fundus oculi Ef (the dimension is distance / time), or the time interval (that is, the time at which the signal light LS is moved to an adjacent scanning point (described later)). The scanning speed can also be defined as the measurement time interval.

  The scanning speed setting unit 235 can set the scanning speed with reference to other setting contents. For example, the scanning speed setting unit 235 sets the scanning speed with reference to the output intensity set by the output intensity setting unit 233. This process is performed based on, for example, information that associates the output intensity with the scanning speed. The scanning speed is set so that, for example, the cumulative amount of light applied to the eye E falls within a safe range.

  The scanning speed setting unit 235 sets the scanning speed with reference to the light emission time set by the light emission time setting unit 234. At this time, the scanning speed (measurement time interval) is set to be synchronized with the light emission time.

  The scanning position setting unit 236 sets the scanning position of the signal light LS. As described later, the scanning position is set as the position of the scanning point (the scanning line is also determined by the arrangement of the scanning points).

  The scanning position setting unit 236 can set the scanning position with reference to other setting contents. For example, the scanning position setting unit 236 sets the scanning position with reference to the output intensity set by the output intensity setting unit 233. In this process, for example, the number of scanning points is determined so that the accumulated amount of light applied to the eye E falls within a safe range, and the scanning positions are set by arranging these scanning points at equal intervals.

  The scanning position setting unit 236 sets the scanning position with reference to the light emission time set by the light emission time setting unit 234. In this process, for example, the number of scanning points is determined on the basis of a (preliminary) scanning time and light emission time in consideration of the effect of positional displacement due to eye movement, and these scanning points are arranged at equal intervals. By doing so, the scanning position is set.

  The accumulation time setting unit 237 sets the charge accumulation time by the CCD 184. Hereinafter, an example of this process will be described. Similar to the output intensity setting process described above, the accumulation time setting unit 237 can increase the accumulation time by a preset amount, or the accumulation time can be set based on the difference between the intensity of the detection signal and the predetermined threshold. The increase amount can also be calculated.

  Note that the scanning speed setting unit 235 can set the scanning speed of the signal light LS with reference to the accumulation time set by the accumulation time setting unit 237. Further, the scanning position setting unit 236 can set the scanning position of the signal light LS based on the set accumulation time. The scanning speed and scanning position are set so as to be synchronized with the accumulation time.

  Here, the control timing of the scanning unit 141, the low coherence light source 160, and the CCD 184 will be described with reference to FIGS. Here, the timing chart shown in FIG. 7 represents the control timing before the control content is changed. The timing chart shown in FIG. 8 represents the control content after the change. In this example, it is assumed that the frame intervals are the same before and after the change.

  In the control timing shown in FIG. 7, first, at time t1, it starts measuring the first scanning point. That is, at time t1, the low-coherence light source 160 is controlled to start the output of the low-coherence light L0, and at the same time, the CCD 184 is controlled to start charge accumulation. There may be a slight deviation between these control timings. For example, by controlling the CCD 184 slightly before the control of the low coherence light source 160, a margin can be provided so as not to fail to detect the low coherence light L0 at the start of output.

  Next, at time t2, the low-coherence light source 160 is controlled to stop the output of the low-coherence light L0.

  Subsequently, at time t3, the CCD 184 is controlled to stop the charge accumulation. The charge accumulation by the CCD 184 actually ends at the time t2, but at the control timing, the charge accumulation is stopped at the time t3 after the time t2, thereby reducing the charge accumulation immediately before the output is stopped. A margin is provided so as not to fail to detect the coherence light L0. Thus, the measurement of the first scanning point is completed.

  Next, between time t4 and time t5, the scanning unit 141 is controlled to move the irradiation position of the signal light LS. Thereby, the irradiation position of the signal light LS moves to the second scanning point.

  At time t6, the output of the low-coherence light L0 is started and the charge accumulation is started, and the measurement of the second scanning point is started. Here again, control is performed at the same timing to measure the second scanning point. Similarly, measurement of the third scanning point is started at time t11. The frame interval of this control timing is t (k + 5) −tk (k = 1, 2,...).

  The intensity of the detection signal obtained by carrying out measurements in such control timing is assumed to be less than a predetermined threshold value. In response to this, the control setting unit 232 sets a new control timing.

  The control setting unit 232 sets the light emission time of the low coherence light L0, and further sets the scanning speed of the signal light LS according to the new light emission time. The control timing shown in FIG. 8 is set in this way.

  At the control timing shown in FIG. 8, first, measurement of the first scanning point is started at the same time t1 as before the change. That is, at time t1, the output of the low-coherence light L0 is started and the charge accumulation is started. Note that these control timing deviations are the same as before the change.

  Next, at a time T2 different from that before the change, the low-coherence light source 160 is controlled to stop the output of the low-coherence light L0. Here, T2> t2. That is, since the light emission time setting unit 234 sets the light emission time of the low coherence light L0 longer than before the change, T2−t1> t2−t1, that is, T2> t2.

  Subsequently, in a different time T3 before the change, to stop the accumulation of the charge by controlling the CCD 184. The charge accumulation actually ends at time T2, but a margin is provided by stopping the charge accumulation at time T3 after time T2. The storage time T3-t1 after the change is set longer by the storage time setting unit 237 than the storage time t3-t1 before the change (that is, T3> t3). Here, when the accumulation time t3 before the change is set after the time T2, it is not necessary to newly set the accumulation time. Thus, the measurement of the first scanning point is completed.

  Next, at time T4 different from that before the change, the scanning unit 141 is controlled to start the movement of the irradiation position of the signal light LS. Time T4 is set after time T2 and further after time T3.

  Subsequently, at the same time t5 as before the change, the scanning unit 141 is controlled to stop the movement of the irradiation position of the signal light LS. Thereby, the irradiation position of the signal light LS moves to the second scanning point.

  Here, if the distance between the first scanning point and the second scanning point is the same, considering that the movement time t5-T4 after the change is shorter than the movement time t5-t4 before the change ( t5-T4 <t5-t4), the scanning speed after the change must be faster than before the change. The scanning speed setting unit 235 sets a new scanning speed based on the changed light emission time (and the changed accumulation time) so as to satisfy this condition.

  Next, measurement of the second scanning point is started at the same time t6 as before the change. Here again, control is performed at the same timing to measure the second scanning point. Similarly, measurement of the third scanning point is started at time t11.

  In the above example, the case where the scanning speed is newly set has been described, but the same applies to the case where the scanning position is newly set. When the scanning speed is not changed, some of the scanning points before the change (for example, every other scanning point) are set as new scanning points along with the extension of the light emission time, etc. Some of them (for example, every other) can be set as new scanning lines. Further, both the scanning speed and the scanning position may be changed.

  Also, when the output intensity of the low coherence light L0 is increased, similarly to the above example, it is possible to newly set the scanning speed, the scanning position, and the accumulation time according to the increase amount. Furthermore, the light emission time can be changed according to the increase amount of the output intensity.

  The data processing unit 238 processes image data and detection signals. Hereinafter, an example of processing executed by the data processing unit 238 will be described.

  As a first processing example, the data processing unit 238 generates an image (superimposed image) in which two or more images obtained by measuring (substantially) the same position on the fundus oculi Ef are superimposed. This superimposed image is obtained by superimposing two or more images along the same scanning line, for example.

  The image superimposing process is executed as follows, for example. First, image alignment is performed as necessary. This process is executed, for example, by searching a characteristic area such as a cross section of a blood vessel or a morphological characteristic part (macular part or the like) from each image and matching the positions of the characteristic areas. When each image is a part of a three-dimensional image, alignment can be performed using an integrated image obtained by integrating the three-dimensional image in the depth direction of the fundus oculi Ef (for example, Japanese Patent Application Laid-Open No. 2007-2007). No. 130403). By such alignment, two or more images are associated in pixel units.

  When the images are aligned, the pixel values (luminance values etc.) of two or more associated pixels are added together. At this time, the value of the sum of the pixel values is divided by the number of associated pixels (that is, the number of images to be superimposed) as necessary.

  New image data is generated by the pixels having the pixel values obtained in this way. This new image data is the image data of the superimposed image. Thereby, a superimposed image with sharp brightness is obtained.

  As a second process example, the data processing unit 238 performs predetermined image processing on an OCT image. Examples of this image processing include averaging processing and filtering processing. The averaging process is a process for averaging the distribution of pixel values in the image. For example, when subjected to averaging processing on the luminance image, brightness distribution in the image is made uniform. The filtering process is a process of correcting the pixel value of a certain pixel based on the pixel values of surrounding pixels. By performing such image processing, the image quality can be improved.

  As a third processing example, the data processing unit 238 performs signal processing for increasing the amplitude of the detection signal. This signal processing is, for example, processing for removing noise included in the detection signal. This includes the process of removing a portion of the noise contained in the detection signal, that is processing for noise reduction are also included. A new detection signal obtained by removing the noise is sent to the image forming unit 220. The image forming unit 220 forms an OCT image (tomographic image) based on the new detection signal.

  The image processing unit 230 described above includes a microprocessor 201, a RAM 202, a ROM 203, a hard disk drive 204 (control program 204a), and the like.

  The image forming unit 220 and the image processing unit 230 (particularly the data processing unit 238) are included in the “image forming unit” of the present invention. The control unit 210 and the control setting unit 232 are included in the “control unit” of the present invention.

(User interface)
A user interface (UI) 240 is provided with a display unit 240A and an operation unit 240B. The display unit 240A includes a display device such as the display 207. The operation unit 240B includes input devices such as a keyboard 205 and a mouse 206, and operation devices.

[Signal light scanning and image processing]
An example of the scanning mode of the signal light LS and the mode of image processing will be described. The signal light LS is scanned by the scanning unit 141. More specifically, the signal light LS is scanned by the control unit 210 controlling the mirror driving mechanisms 241 and 242 to change the direction of the reflecting surfaces of the galvanometer mirrors 141A and 141B.

  The galvanometer mirror 141A scans the signal light LS in the horizontal direction (x direction in FIG. 1). Galvano mirror 141B scans the signal light LS vertical direction (y direction in FIG. 1). Further, the signal light LS can be scanned in an arbitrary direction on the xy plane by simultaneously operating both the galvanometer mirrors 141A and 141B.

  FIG. 9 illustrates an example of a scanning mode of the signal light LS for forming an image of the fundus oculi Ef. FIG. 9A illustrates an example of a scanning mode of the signal light LS when the fundus oculi Ef is viewed from the direction in which the signal light LS is incident on the eye E (that is, viewed from the −z direction to the + z direction in FIG. 1). Represents. FIG. 9B shows an example of an arrangement mode of scanning points (measurement positions) in each scanning line on the fundus oculi Ef.

  As shown in FIG. 9A, the signal light LS is scanned in a rectangular scanning region R. In the scanning region R, a plurality (m) of scanning lines R1 to Rm along the x direction are set. The scanning lines Ri (i = 1 to m) are arranged in the y direction. The direction (x direction) of each scanning line Ri is referred to as “main scanning direction”, and the direction (y direction) perpendicular thereto is referred to as “sub scanning direction”.

  On each scanning line Ri, as shown in FIG. 9B, a plurality (n) of scanning points Ri1 to Rin are set. Note that the positions of the scanning region R, the scanning line Ri, and the scanning point Rij are appropriately set before measurement.

  In order to execute the scanning shown in FIG. 9, the control unit 210 first controls the galvanometer mirrors 141A and 141B to set the incidence target of the signal light LS on the fundus oculi Ef to the scanning start position RS ( Set to scan point R11). Subsequently, the control unit 210 controls the low coherence light source 160 to cause the low coherence light L0 to flash and cause the signal light LS to enter the scan start position RS. The CCD 184 receives the interference light LC based on the reflected light at the scanning start position RS of the signal light LS, accumulates charges, and generates a detection signal.

  Next, the control unit 210 controls the galvanometer mirror 141A, scans the signal light LS in the main scanning direction, sets the incident target at the scanning point R12, flashes the low coherence light L0, and scans the scanning point. The signal light LS is incident on R12. The CCD 184 receives the interference light LC based on the reflected light of the signal light LS at the scanning point R12, accumulates charges, and generates a detection signal.

  Similarly, the controller 210 sequentially flashes the low coherence light L0 at each scanning point while sequentially moving the incident target of the signal light LS from the scanning points R13, R14,..., R1 (n−1), R1n. By emitting light, a detection signal corresponding to each scanning point is generated.

  When the measurement at the last scanning point R1n of the first scanning line R1 is completed, the control unit 210 controls the galvanometer mirrors 141A and 141B at the same time so that the incident target of the signal light LS is changed along the line changing scan r. The second scanning line R2 is moved to the first scanning point R21. And the control part 210 performs the same measurement about each scanning point R2j (j = 1-n) of this 2nd scanning line R2, and produces | generates the detection signal corresponding to each scanning point R2j, respectively.

  Similarly, the control unit 210 performs measurement for each of the third scanning line R3,..., The (m−1) th scanning line R (m−1), and the mth scanning line Rm. A detection signal corresponding to the point is generated. Note that the symbol RE on the scanning line Rm is a scanning end position corresponding to the scanning point Rmn.

  In this way, the control unit 210 generates m × n detection signals corresponding to m × n scanning points Rij (i = 1 to m, j = 1 to n) in the scanning region R. A detection signal corresponding to the scanning point Rij may be represented as Dij.

  In the above control, the control unit 210 acquires position information (coordinates in the xy coordinate system) of each scanning point Rij when the galvanometer mirrors 141A and 141B are operated. This position information (scanning position information) is referred to when an OCT image is formed.

  Next, an example of image processing when the scan shown in FIG. 9 is performed will be described.

  The image forming unit 220 forms a tomographic image of the fundus oculi Ef along each scanning line Ri (main scanning direction). The image processing unit 230 forms a three-dimensional image of the fundus oculi Ef based on the tomographic image formed by the image forming unit 220.

  The tomographic image forming process includes a two-stage arithmetic process, as in the prior art. In the first stage, an image in the depth direction (z direction shown in FIG. 1) of the fundus oculi Ef at the scanning point Rij is formed based on each detection signal Dij.

  In the second stage, images in the depth direction at the scanning points Ri1 to Rin are arranged based on the scanning position information, and a tomographic image Gi along the scanning line Ri is formed. Through the above processing, m tomographic images G1 to Gm are obtained.

  The image processing unit 230 arranges the tomographic images G1 to Gm based on the scanning position information, performs an interpolation process for interpolating an image between the adjacent tomographic images Gi and G (i + 1), and the like, and performs three-dimensional processing of the fundus oculi Ef. Generate an image. This three-dimensional image is defined by, for example, a three-dimensional coordinate system (x, y, z) based on scanning position information.

  Further, the image processing unit 230, based on this 3-dimensional image, can form a tomographic image at an arbitrary cross-section. When the cross section is designated, the image processing unit 230 identifies the position of each scanning point (and / or the interpolated depth direction image) on the designated cross section, and the depth direction image (and / or at each specific position). The interpolated depth direction image) is extracted from the three-dimensional image, and the extracted plurality of depth direction images are arranged based on the scanning position information and the like, thereby forming a tomographic image at the designated cross section.

  Note that an image Gmj shown in FIG. 10 represents an image in the depth direction at the scanning point Rmj on the scanning line Rm. Similarly, an image in the depth direction at the scanning point Rij, which is formed in the above-described first stage processing, is represented as “image Gij”.

  Scanning of the signal light LS by the fundus observation device 1 is not limited to those described above. For example, the signal light LS is scanned only in the horizontal direction (x direction), scanned only in the vertical direction (y direction), scanned vertically and horizontally in a cross shape, scanned radially, or in a circular shape. or by scanning, or by scanning concentrically, can or by scanning in a spiral shape. That is, as described above, since the scanning unit 141 is configured to be able to scan the signal light LS independently in the x direction and the y direction, it scans the signal light LS along an arbitrary locus on the xy plane. Is possible.

[Usage form]
A usage pattern of the fundus oculi observation device 1 will be described. The flowcharts shown in FIGS. 11 to 13 are examples of usage patterns of the fundus oculi observation device 1.

  First, alignment of the optical system with respect to the eye E is performed (S1). Alignment is performed in the same manner as a conventional fundus camera. For example, alignment is performed by projecting an alignment bright spot (not shown) onto the eye E and adjusting the position of the fundus camera unit 1A while observing the state.

  Next, the position of the reference mirror 174 is adjusted, and the interference state between the signal light and the reference light is adjusted (S2). At this time, the image of a desired depth position of the fundus oculi Ef is adjusted so as to clear. The position adjustment of the reference mirror 174 may be performed manually using the operation unit 240B or may be performed automatically.

  Next, an image of the fundus oculi Ef is acquired (S3). At this time, for example, measurement is performed by applying the control mode shown in the timing chart of FIG. 7 and the scanning mode shown in FIG. This image is for evaluating whether a suitable image can be obtained under the measurement condition (referred to as an evaluation image). The main control unit 211 displays this evaluation image on the display unit 240A (S4).

  Based on the detection signal (frequency component) of the interference light LC or the evaluation image, the intensity determination unit 231 determines the magnitude relationship by comparing the intensity of the detection signal with a predetermined threshold (S5).

[When the intensity of the detection signal is equal to or greater than a predetermined threshold value]
When it is determined that the intensity of the detection signal is equal to or greater than the predetermined threshold (S6; Y), the main control unit 211 causes the display unit 240A to display information indicating that the measurement condition is appropriate (S7). This display information is, for example, an OK mark or a predetermined message. Further, the evaluation image or the like may be displayed in a predetermined color (for example, blue or green). Also, voice information can be output.

  The operator instructs acquisition of an image using the operation unit 240B (S8). This instruction is performed, for example, by pressing a photographing button as in a conventional fundus camera. In response to this instruction, the main control unit 211 performs measurement under the same measurement conditions as the evaluation image, and acquires an image (S9). Then, the main control unit 211 displays this image on the display unit 240A (S10). This is the end of the process in this case. This image is used for observation by a doctor or the like.

[When the intensity of the detection signal is less than the predetermined threshold value]
On the other hand, when it is determined that the intensity of the detection signal is less than the predetermined threshold (S6; N), the main control unit 211 causes the display unit 240A to display information indicating that the measurement condition is not appropriate (S11). This display information is, for example, a message such as “the signal is weak” or a numerical value indicating the signal strength. Further, the evaluation image or the like may be displayed in a predetermined color (for example, red). Also, voice information can be output.

  Further, the control setting unit 232 sets a new measurement condition (S12). At this time, the control mode shown in the timing chart of FIG. 8 is set. In addition, when a scanning position is newly set, the scanning mode of FIG. 9 is also changed. However, in general, the arrangement of scanning lines is not changed (the number of scanning lines may be changed).

  The main control unit 211 performs measurement under the new measurement condition and acquires an image (S13). Further, the main control unit 211 displays this image on the display unit 240A (S14).

  The intensity determining unit 231 determines the magnitude relationship by comparing the intensity of the detection signal with a predetermined threshold based on the detection signal (frequency component) or image obtained under the new measurement condition (S15).

  When it is determined that the intensity of the detection signal is equal to or greater than the predetermined threshold (S16; Y), the main control unit 211 causes the display unit 240A to display information indicating that the measurement condition is appropriate (S17).

  The operator instructs acquisition of an image using the operation unit 240B (S18). In response to this instruction, the main control unit 211 performs measurement under the measurement conditions and acquires an image (S19). Then, the main control unit 211 displays this image on the display unit 240A (S20). This image is used for observation by a doctor or the like.

  The main control unit 211 stores the measurement condition (and scanning mode) in the storage unit 212 together with the patient information of the subject (S21). Note that the storage destination of these pieces of information may be another storage device. As described above, by storing the measurement conditions and the like, the measurement conditions and the like can be automatically reproduced in a future inspection. This is the end of the process in this case.

  On the other hand, when it is determined that the intensity of the detection signal is less than the predetermined threshold (S16; N), the main control unit 211 causes the display unit 240A to display information for selecting whether or not to process the image ( S22).

  The operator operates the operation unit 240B, selects whether to perform the processing (S23). When the processing is not performed (S23; N), the main control unit 211 causes the display unit 240A to display information indicating that a suitable image cannot be acquired (S24). This is the end of the process in this case.

  A case where a superimposed image is generated as data processing will be described (S23; Y). In this case, in step 22, the number of images to be superimposed can be set. Further, the control setting unit 232 may newly set measurement conditions as necessary.

  The main control unit 211 controls the low coherence light source 160, the scanning unit 141, the CCD 184, and the like to acquire a predetermined number of images (S25). The data processing unit 238 superimposes these images to generate a superimposed image (S26).

  The main control unit 211 displays the superimposed image on the display unit 240A (S27). In addition, the main control unit 211 stores the measurement condition (and scanning mode) in the storage unit 212 together with the patient information of the subject (S28). This is the end of the process in this case.

  When image processing is performed as data processing, the main control unit 211 acquires a new image, and the data processing unit 238 performs image processing on the new image.

  When the amplitude of the detection signal is increased as data processing, the main control unit 211 performs a new measurement, and the data processing unit 238 increases the amplitude of the detection signal obtained thereby to newly It generates Do detection signal, the image forming unit 220 forms an image on the basis of the new detection signal.

[Action / Effect]
The operation and effect of the fundus oculi observation device 1 as described above will be described.

  The fundus oculi observation device 1 divides the low-coherence light L0 into the signal light LS and the reference light LR, and superimposes the signal light LS passing through the fundus oculi Ef and the reference light LR passing through the reference mirror 174 to generate the interference light LR. It generates and detects the interference light LC, generates a detection signal, and functions as an optical image measurement device that forms an image of the fundus oculi Ef based on the detection signal. Further, the fundus oculi observation device 1 determines whether the intensity of the detection signal of the interference light LC is equal to or greater than a predetermined threshold, and increases the intensity of the detection signal of the interference light LC when it is determined that the intensity is less than the predetermined threshold. Control is performed.

  The interference light LC is detected by the CCD 184. The CCD 184 receives the interference light LC and converts it into charges, accumulates the charges, and generates a detection signal. The control unit 210 acts to increase the intensity of the detection signal by performing control so as to increase the amount of charge accumulated by the CCD 184.

  In particular, the fundus oculi observation device 1 performs the following control in order to increase the charge accumulation amount: (1) increase the charge accumulation time by the CCD 184; (2) increase the output time of the low coherence light L0. (3) Increase the output intensity of the low coherence light. It should be noted that the setting of these control details may be performed individually or in cooperation with each other.

  Further, the detection signal intensity determination process includes the following. As a first determination process, there is a method of determining the intensity of the detection signal by determining whether the minimum value of the frequency component intensity of the detection signal is equal to or greater than a predetermined value. In this case, when it is determined that the minimum value is less than the predetermined value, it is desirable to increase the intensity of the detection signal of the interference light LC so that the frequency component corresponding to the minimum value is equal to or greater than the predetermined value. . Incidentally, when its not increase the strength so it may be subjected to data processing described above.

  As a second determination process, there is a method of determining the intensity of the detection signal by determining whether the maximum value of the pixel values of the pixels constituting the image is equal to or greater than a predetermined value. In this case, when it is determined that the maximum value is less than the predetermined value, the intensity of the detection signal of the interference light LC is increased so that the pixel value of the pixel corresponding to the maximum value is equal to or greater than the predetermined value. Is desirable. When the strength cannot be increased in this way, the data processing described above can be performed.

  As a third determination process, the intensity of the detection signal is determined by identifying pixels having a pixel value equal to or greater than a predetermined value from among the pixels constituting the image and determining whether the number of these pixels is equal to or greater than the predetermined number. There is a technique to do. In this case, when it is determined that this number is less than the predetermined number, it is desirable to increase the intensity of the detection signal of the interference light LC so that the number of such pixels is equal to or greater than the predetermined number. When the strength cannot be increased in this way, the data processing described above can be performed.

  Further, the fundus oculi observation device 1 determines whether the intensity of the detection signal obtained after setting the new control content is equal to or greater than a predetermined threshold. When it is determined that the new intensity is less than the predetermined threshold, the fundus oculi observation device 1 forms a superimposed image by superimposing two or more images. The superimposed image is clearer than the original images. Further, the image can be clarified by performing predetermined image processing on the image or performing signal processing for increasing the amplitude of the detection signal.

  According to such a fundus oculi observation device 1, even when the intensity of the interference light LC is low, the intensity of the detection signal of the interference light LC can be increased, so that a clear image can be acquired.

  When the intensity of the detection signal cannot be increased sufficiently, the image can be clarified by forming a superimposed image, performing image processing, or increasing the amplitude of the detection signal. it can.

[Modification]
The configuration described above is merely an example for favorably implementing the optical image measurement device according to the present invention. Therefore, arbitrary modifications within the scope of the present invention can be made as appropriate.

  In the above embodiment, the output intensity and emission time of the low-coherence light L0, the scanning speed and scanning position of the signal light LS, the accumulation time of the CCD 184, etc. are automatically set. It can be configured to do so. In that case, a screen for setting these is displayed on the display unit 240A. The operator can set desired control contents manually by controlling the operation unit 240B. In addition, after setting automatically like the said embodiment, it is also possible to display the setting content and to be able to change it manually.

  In the above embodiment, the superimposed image is formed when the intensity of the detection signal of the interference light is not increased enough, but the superimposed image is formed in other situations. It is also possible to do.

  For example, when it is determined that the intensity of the detection signal corresponding to the evaluation image is less than a predetermined threshold value, two or more images can be formed, and these images can be superimposed to form a superimposed image. According to such a configuration, the image can be clarified even when the intensity of the detection signal is not sufficient.

  In the above-described embodiment, predetermined image processing (such as averaging processing or filtering processing is performed when the intensity of the interference light detection signal is not increased enough to increase the intensity. It is also possible to configure so as to perform image processing in the above situation.

  For example, when it is determined that the intensity of the detection signal corresponding to the evaluation image is less than a predetermined threshold value, image processing can be performed on the image (evaluation image or newly acquired image). According to such a configuration, the image can be clarified even when the intensity of the detection signal is not sufficient.

  Further, in the above-described embodiment, signal processing is performed to increase the amplitude of the detection signal when the intensity of the detection signal of the interference light is not sufficient even when the intensity is increased, but in other situations It is also possible to configure to perform the signal processing.

  For example, when it is determined that the intensity of the detection signal corresponding to the evaluation image is less than a predetermined threshold, the detection signal (the detection signal corresponding to the evaluation image or the newly acquired detection signal) Processing can be performed. According to such a configuration, the image can be clarified even when the intensity of the detection signal is not sufficient.

  In the above embodiment, the position of the reference mirror 174 is changed to change the optical path length difference between the optical path of the signal light LS and the optical path of the reference light LR. However, the method of changing the optical path length difference is limited to this. Is not to be done. For example, the optical path length difference can be changed by moving the fundus camera unit 1A and the OCT unit 150 integrally with the eye E to change the optical path length of the signal light LS. In particular, when the measured object is not a living body, the optical path length difference can be changed by moving the measured object in the depth direction (z direction).

  In the above-described embodiment, an apparatus that acquires an OCT image of the fundus has been described. However, the configuration of the above-described embodiment is also applied to an apparatus that can acquire an OCT image of another part of the subject's eye such as the cornea. Is possible. The present invention can also be applied to an optical image measurement device that measures OCT images of various measurement objects other than eyes. For example, the optical image measurement device according to the present invention can be applied to arbitrary fields such as the engineering field and the biological field.

  The control program 204a in the above embodiment can be stored in any recording medium that can be read by the drive device of the computer. As this recording medium, for example, an optical disk, a magneto-optical disk (CD-ROM / DVD-RAM / DVD-ROM / MO, etc.), a magnetic storage medium (hard disk / floppy (registered trademark) disk / ZIP, etc.), etc. are used. Is possible. It can also be stored in a storage device such as a hard disk drive or memory. Further, this program can be transmitted through a network such as the Internet or a LAN.

It is a schematic block diagram showing an example of the whole structure of embodiment of the fundus oculi observation device functioning as the optical image measurement device according to the present invention. It is a schematic block diagram showing an example of a structure of the scanning unit incorporated in the fundus camera unit in the embodiment of the fundus oculi observation device functioning as the optical image measurement device according to the present invention. It is a schematic block diagram showing an example of a structure of the OCT unit in embodiment of the fundus oculi observation device functioning as the optical image measurement device according to the present invention. It is a schematic block diagram showing an example of the hardware constitutions of the calculation control apparatus in embodiment of the fundus oculi observation device functioning as the optical image measurement device according to the present invention. It is a schematic block diagram showing an example of the structure of the control system of embodiment of the fundus oculi observation device functioning as the optical image measurement device according to the present invention. It is a schematic block diagram showing an example of the structure of the control system of embodiment of the fundus oculi observation device functioning as the optical image measurement device according to the present invention. It is a timing chart showing an example of the timing of control by the embodiment of the fundus oculi observation device functioning as the optical image measurement device according to the present invention. It is a timing chart showing an example of the timing of control by the embodiment of the fundus oculi observation device functioning as the optical image measurement device according to the present invention. It is the schematic showing an example of the scanning aspect of the signal light by embodiment of the fundus oculi observation device functioning as an optical image measuring device concerning this invention. FIG. 9A illustrates an example of a scanning mode of the signal light when the fundus is viewed from the signal light incident side with respect to the eye to be examined. Further, FIG. 9 (B) represents one example of arrangement features of scanning points on each scan line. It is the schematic showing an example of the scanning aspect of the signal light by embodiment of the fundus oculi observation device functioning as the optical image measurement device according to the present invention, and the aspect of the tomographic image formed along each scanning line. It is a flowchart showing an example of the usage pattern of embodiment of the fundus oculi observation device functioning as the optical image measurement device according to the present invention. It is a flowchart showing an example of the usage pattern of embodiment of the fundus oculi observation device functioning as the optical image measurement device according to the present invention. It is a flowchart showing an example of the usage pattern of embodiment of the fundus oculi observation device functioning as the optical image measurement device according to the present invention.

Explanation of symbols

1 Fundus observation device (optical image measurement device)
1A Fundus camera unit 141 Scan unit 150 OCT unit 160 Low coherence light source 174 Reference mirror 180 Spectrometer 184 CCD
200 arithmetic control unit 210 control unit 220 image forming unit 221 frequency component calculating unit 230 image processing unit 231 intensity determining unit 232 control setting unit 233 output intensity setting unit 234 light emission time setting unit 235 scanning speed setting unit 236 scanning position setting unit 237 accumulation Time setting unit 238 Data processing unit 240 User interface

Claims (22)

Dividing the light output from the optical source into a signal light and a reference light, an interference light generating means for generating interference light by superimposing the reference light propagated through a reference object and the signal light propagated through the object to be measured ,
Detecting means for detecting the interference light and generating a detection signal;
Image forming means for forming an evaluation image of the object to be measured based on the detection signal;
Determination means for determining whether the intensity of the detection signal is equal to or higher than a predetermined threshold after the evaluation image is formed ;
Control means for performing control to increase the intensity of the detection signal of the interference light when it is determined that the intensity is less than a predetermined threshold;
With
The image forming unit forms an image of the object to be measured based on a detection signal having an increased intensity;
An optical image measuring device characterized by that. The detection means receives the interference light and converts it into charges, accumulates the charges and generates a detection signal,
The control means increases the intensity of the interference light detection signal by performing control so as to increase the amount of charge accumulated by the detection means,
The optical image measuring device according to claim 1. The control means controls the detection means to increase the accumulation amount by increasing the charge accumulation time;
The optical image measuring device according to claim 2. The interference light generating means includes scanning means for scanning the irradiation position of the signal light on the object to be measured.
The control means controls the scanning means to scan the signal light at a scanning speed corresponding to the increased accumulation time;
The optical image measuring device according to claim 3. The interference light generating means includes scanning means for scanning the irradiation position of the signal light on the object to be measured.
The control unit controls the scanning unit to sequentially irradiate the signal light to the number of scanning points according to the increased accumulation time.
The optical image measuring device according to claim 3. The control means increases the accumulation amount by increasing the light output time by controlling the light source,
The optical image measuring device according to claim 2. The interference light generating means includes scanning means for scanning the irradiation position of the signal light on the object to be measured.
The control means controls the scanning means to obtain a scanning speed corresponding to the increased output time, and scans the signal light at the scanning speed.
The optical image measuring device according to claim 6. The interference light generating means includes scanning means for scanning the irradiation position of the signal light on the object to be measured.
The control means controls the scanning means to determine the number of scanning points according to the increased output time, and sequentially irradiates the number of scanning points with signal light.
The optical image measuring device according to claim 6. The control means increases the accumulation amount by increasing the output intensity of light by controlling the light source,
The optical image measuring device according to claim 2. The interference light generating means includes scanning means for scanning the irradiation position of the signal light on the object to be measured.
The control means controls the scanning means to scan the signal light at a scanning speed corresponding to the increased output intensity.
The optical image measuring device according to claim 9. The interference light generating means includes scanning means for scanning the irradiation position of the signal light on the object to be measured.
The control means controls the scanning means to sequentially irradiate the signal light to the number of scanning points according to the increased output intensity.
The optical image measuring device according to claim 9. The image forming means includes a calculating means for obtaining a plurality of frequency components of the detection signal,
The determination means specifies a minimum value of the intensities of the plurality of frequency components, determines the intensity of the detection signal by determining whether the minimum value is a predetermined value or more,
The control means, when it is determined that the minimum value is less than a predetermined value, increases the intensity of the interference light detection signal so that a frequency component corresponding to the minimum value is equal to or greater than a predetermined value.
The optical image measurement device according to any one of claims 1 to 11, wherein the optical image measurement device is an optical image measurement device. The determining means determines a maximum value of pixel values of a plurality of pixels of the image, determines the intensity of the detection signal by determining whether the maximum value is a predetermined value or more,
The control means, when it is determined that the maximum value is less than a predetermined value, increases the intensity of the interference light detection signal so that the pixel value of the pixel corresponding to the maximum value is equal to or greater than a predetermined value.
The optical image measurement device according to any one of claims 1 to 11, wherein the optical image measurement device is an optical image measurement device. The determination means specifies a pixel having a pixel value equal to or greater than a predetermined value among a plurality of pixels of the image, and determines the intensity of the detection signal by determining whether the number of the specified pixel is equal to or greater than a predetermined number. Judgment
The control means increases the intensity of the interference light detection signal so that the number of pixels having a pixel value equal to or greater than a predetermined value is equal to or greater than a predetermined number when the number is determined to be less than the predetermined number;
The optical image measurement device according to any one of claims 1 to 11, wherein the optical image measurement device is an optical image measurement device. The determination means determines whether the intensity of the detection signal of the new interference light after the control by the control means is equal to or greater than the predetermined threshold;
The control unit controls the light source, the detection unit, and the image forming unit to form two or more images when it is determined that the new intensity is less than a predetermined threshold, and the two or more images are formed. To form a new image,
The optical image measurement device according to any one of claims 1 to 11, wherein the optical image measurement device is an optical image measurement device. The determination unit determines whether the intensity of a new detection signal after control by the control unit is equal to or greater than the predetermined threshold value.
The control means controls the image forming means when it is determined that the new intensity is less than a predetermined threshold, and performs predetermined image processing for improving image quality on the image.
The optical image measurement device according to any one of claims 1 to 11, wherein the optical image measurement device is an optical image measurement device. The determination means determines whether the intensity of the detection signal of the new interference light after the control by the control means is equal to or greater than the predetermined threshold;
When it is determined that the new intensity is less than a predetermined threshold, the control unit controls the image forming unit, increases the amplitude of the detection signal, generates a new detection signal, and generates the new detection signal. Forming an image based on the detection signal;
The optical image measurement device according to any one of claims 1 to 11, wherein the optical image measurement device is an optical image measurement device. Dividing the light output from the optical source into a signal light and a reference light, an interference light generating means for generating interference light by superimposing the reference light propagated through a reference object and the signal light propagated through the object to be measured ,
Detecting means for detecting the interference light and generating a detection signal;
Image forming means for forming an evaluation image of the object to be measured based on the detection signal;
Determination means for determining whether the intensity of the detection signal is equal to or higher than a predetermined threshold after the evaluation image is formed ;
When it is determined that the intensity is less than a predetermined threshold, the light source, the detection signal, and the image forming unit are controlled to form two or more images, and the two or more images are superposed to form a new image. Control means for forming
An optical image measurement device comprising: Dividing the light output from the optical source into a signal light and a reference light, an interference light generating means for generating interference light by superimposing the reference light propagated through a reference object and the signal light propagated through the object to be measured ,
Detecting means for detecting the interference light and generating a detection signal;
Image forming means for forming an evaluation image of the object to be measured based on the detection signal;
Determination means for determining whether the intensity of the detection signal is equal to or higher than a predetermined threshold after the evaluation image is formed ;
Control means for controlling the image forming means when the intensity is determined to be less than a predetermined threshold, and performing predetermined image processing for improving image quality on the image;
An optical image measurement device comprising: The predetermined image processing is averaging processing for averaging distribution of pixel values in the image, or filtering processing for correcting pixel values based on pixel values of surrounding pixels for the pixels of the image.
20. The optical image measuring device according to claim 16 or claim 19, wherein Dividing the light output from the optical source into a signal light and a reference light, an interference light generating means for generating interference light by superimposing the reference light propagated through a reference object and the signal light propagated through the object to be measured ,
Detecting means for detecting the interference light and generating a detection signal;
An image forming means for forming an image of the object to be measured based on the detection signal;
Determining means for determining whether the intensity of the detection signal is equal to or greater than a predetermined threshold;
When it is determined that the intensity is less than a predetermined threshold, the image forming unit is controlled to increase the amplitude of the detection signal to generate a new detection signal, and form an image based on the new detection signal Control means for causing
An optical image measurement device comprising: The image forming unit generates the new detection signal by removing noise included in the detection signal;
The optical image measurement device according to claim 17 or claim 21, wherein

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